On 15.02.13 13:10, andy pugh wrote: > On 15 February 2013 12:48, Erik Christiansen <[email protected]> wrote: > > > I only want to use it on a hobbing and dividing gadget, so might get > > away with belt drive within the 75N limit, but only if I only ever use > > half of its torque, given your figures. No, that would use up the whole > > allowance in the torque force! I can pretension to 37N, and use 1/4 of > > the motor torque, IIUC > > I don't think that the forces are additive. The torque will tighten > one run of the belt and loosen the other. Only when the "torque force" > is higher than the pre-tension will the radial load increase. > (equivalent to bolt preload)
Many thanks, Andy. that is good news. > Bigger pulleys reduce the "torque force" Yes, that began to sink in when I ran my mind over your 10 mm radius, 3 Nm, 300 N example. You're right, finding room for bigger pulleys beats the alternative. > The rating is at 20mm from the flange, it should be higher closer to > the bearings. Yes, if the major factor is bending of the cantilevered 1/4" shaft, then there's something to win there. From one of your other finds, a pdf on bearings, I've cottoned onto the inverse proportionality of bearing load and life. > Worst-case you have to replace the bearings every decade... And if the whole motor, that's $6.90 per year. I think you've cut to the core of how to proceed. Erik -- Happiness isn't having what you want, it's wanting what you have. ------------------------------------------------------------------------------ Free Next-Gen Firewall Hardware Offer Buy your Sophos next-gen firewall before the end March 2013 and get the hardware for free! Learn more. http://p.sf.net/sfu/sophos-d2d-feb _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
